Threat from global warming heightened in latest UN report

Smoke billows from the chimneys of a heating plant in Jilin, Jilin province.

Global warming poses a growing threat to the health, economic prospects, and food and water sources of billions of people, top scientists said in a report that urges swift action to counter the effects of carbon emissions.

The latest report from the UN Intergovernmental Panel on Climate Change (IPCC) says the effects of warming are being felt everywhere, fuelling potential food shortages, natural disasters and raising the risk of wars.

"The world, in many cases, is ill-prepared for risks from a changing climate," the IPCC said today, after the final text of the report was agreed.

More warming increased the chance of harsh, widespread impacts that could be surprising or irreversible, it added.

The report projects global warming may cut world economic output by between 0.2 and 2.0 percent a year should mean temperatures rise by 2 degrees Celsius (3.6 Fahrenheit), estimates that many countries say are too low.

"Over the coming decades, climate change will have mostly negative impacts," said Michel Jarraud, Secretary-General of the World Meteorological Organization (WMO), citing cities, ecosystems and water supply as being among the areas at risk.

"The poor and vulnerable will be most affected," he added.

The IPCC was set up in 1988 by the WMO and the United Nations Environment Programme.